A. Field of Invention
This invention pertains to an optical disc, such as CD, a DVD, and the like, that is partially coated with a material having characteristics that are changed when the material is subjected to radiation of a particular frequency, and this change either activates the optical disc so that it can be used in a device, or is disabled so that it cannot be used.
B. Description of the Prior Art
The theft of DVDs, computer and platform games, software, music CDs and other media on optical discs is a growing problem for retailers. Although it is possible to place theft deterrent devices in optical disc packaging, such devices are often unsuccessful in deterring theft. Such devices, which are typically triggered when the consumer exits the store, can be easily overcome by simply removing the optical disc from the package and concealing it on one's person before exiting the store.
Typically, theft of DVDs and other optical disc products housed in the commonly used “clam shell” case is accomplished by cutting the packaging material at the vertical edge of the case where it opens, applying pressure on the top and bottom of the case so that the cut opening expands, and removing the disc. The disc can be removed by either shaking it loose from the center spindle and sliding it out of the opening, or by physically removing it from the spindle by inserting a finger or other device into the opening of the case and applying pressure to the disc so that it is detached from the spindle and can then be easily removed from the case. Theft also occurs by simply opening the case in its entirely and removing the disc in usual fashion. Once the disc, which is smaller than the case, is removed therefrom, it can be easily concealed on one's person—in a pocket or purse—and surreptitiously removed from the retailer's environs. Although various improvements have been made to DVD cases to frustrate the removal of discs in the retail environment, such as by the addition of improved spindles and locking tabs, these approaches have not been fully effective in discouraging theft.
Theft of optical discs containing motion pictures, software and computer games is a significant problem for retailers. DVD discs containing motion pictures typically retail for $20.00 or more; computer and platform games often retail for $50.00 and some software sells for even more. Theft of these products, which are expensive relative to their small size, is a growing problem for retailers; particularly as such items tend to be highly profitable for retailers.
Theft of optical disc in the packaging is also a problem. Some retailers may not be able to afford expensive equipment that detects devices in packaging which, if not disabled, will cause an alarm to be activated when the customer leaves the store, or such devices may be removed from the packaging or the DVD by the customer while inside the store. Thus, certain solutions that to the theft problem such as engineering a theft-proof optical disc container, as disclosed, for example, in U.S. Patent Publication 20030234190 (application Ser. No. 10/178,465), do not provide complete solutions as the container itself with the enclosed disc may be removed from the retail environment without detection. Other approaches that are designed to render a disc unplayable employ oxygen penetrable substrates whereby the data layer corrodes and loses reflectivity upon exposure to air, such as that described in PCT Patent Publication no. 02075733 (application no. PCT/US02/05050) and U.S. Pat. No. 6,733,950. Such approaches, however, are not reversible and cannot be readily employed to fashion a theft deterrent system.